Speakers in Parallel Calculator

The calculator below is useful in determining the total impedance of speakers in parallel. It also calculates how the power is shared between the speakers. If all the speakers have the same impedance, the calculation is relatively simple. 

Simple Impedance Calculation for Speakers in Parallel

If all the speakers in parallel have the same impedance, then the calculation is easy. Simply divide the impedance by the number of speakers in parallel.

Example 1: Four 8 ohm speakers in parallel: 8 divided by 4 = 2 ohms.

Example 2: Two 4 ohms speakers in parallel: 4 divided by 2 = 2 ohms.

Not so Simple Calculations for Speakers in Parallel

For calculations involving speakers in parallel with different impedance, the following formula is required (it can be used with speakers of similar impedances too).

\large{Imp_{Total}}=\frac{1}{\frac{1}{Imp_1}+\frac{1}{Imp_2}+\frac{1}{Imp_3}+ ...}

If you have a calculator with 1/x button then this calculation is not too difficult. If you don’t have that function on your calculator, or if you don’t like formulas, check out the calculator below.

Using the Calculator

The calculator can be used for 2, 3 or 4 speakers wired in parallel. 

Simply type the impedance of each speaker into the white boxes (or use the drop-down values). Use N/A for unused speakers in this calculator. The total impedance will be calculated for the entered speakers.

Also calculated for each speaker is its percentage share of the amplifier’s output power. This is useful as power sharing is a consideration when using speakers with different impedance.

“Power Differential” is the final calculation. This calculates in dB (decibels) the power level difference between the highest and lowest power as it is shared across the speakers. This shows the power level difference when using speakers with different impedance.

Amplifier Power Calculator

The bottom section of the calculator helps in matching the speaker combination with your amplifier. This is not necessary if you only want to know the total impedance and/or the power ratios.

However if you are connecting these speakers to your amplifier, it may be helpful to input the amplifier power and the associated speaker impedance. In the specifications for your amplifier, it should say something like:

Amplifier power: 80 watts continuous average power @ 4 ohms (2 channels driven, THD 0.08%, 20Hz-20kHz)

This tells you the maximum continuous power the amplifier will deliver into a 6 ohm load is 80 watts. In the calculator below, for this example, you type in 80 for the power and 6 for the impedance. Be aware, some specifications state RMS power rather than continuous power. These are effectively the same.

The calculator will display the effective power of the amplifier for the calculated total impedance of the series speakers. Also displayed (under each speaker’s power %) is the actual maximum power the amplifier will supply each connected speaker. A comment on the suitability of the calculated total impedance for your amplifier is also provided.

Download Calculator
as Excel File
Prices in US$

Note: the calculated output power for the amplifier is based on a theoretical “ideal” amplifier. In practise, your amplifier may produce slightly more power.

Further Reading

This calculator will help you understand the total speaker load on your HiFi amplifier. For a better understanding of this and what to do about it, read the articles How do I Connect Multiple Speakers to my HiFi Amplifier and How to wire four HiFi speakers or How to connect 2 speakers to one amplifier or watch the video in the article Understanding Speaker Impedance.Also see How Multiple Speakers Share Power for further details about the percentage power calculations. For more details about the effective amplifier power at higher impedance loads, see How Impedance Changes Amplifier Power.

Please Note: all these calculations are for connecting manufactured speakers (boxes). They are not used when building your own speaker boxes and connecting multiple speakers in a cabinet using a crossover circuit. A crossover splits the signal into different frequencies for each of the speakers and makes the total impedance calculation complex (as impedance is frequency dependent). That is why speaker designers get the big money, and as installers we benefit from their expertise.

If you need further advice on connecting speakers (boxes) in parallel, please read the FAQs before submitting your question. You may also find an answer in the comments below.

Disclosure: If you buy through this Amazon USA link Geoff receives a small commission from each sale.
European and Australian readers can use the links on the side panel - Thanks for the support


Hi Geoff!

I have amplifier which have Dynamic Power 160 W (3 ohms, Front) 125 W (4 Ohms, Front) 85 W (8 Ohms, Front),
I have 6 speakers with 16W 8ohms, can I run them?



Hi Geoff,

I installed new speakers in my car which came with stock Bose speakers because of a deal Pontiac and Bose made back in the late 1990’s. I have 2 4Ohm 30RMS 2-way speakers and 2 4Ohm 75RMS 2-way speakers. I used the stock wires and the speakers are very quiet compared to the stock speakers. I couldn’t find anything on the specs of the Bose speakers or the amp. Would I need new wires or is the amp not putting enough power?


i have two 4 ohm dvc and a 1 channel amp. i need a 2 ohm load out


Hi Geoff,
I have an amp with 2 channel @ 4 ohm/750W each. (2x Left and 2x Right). I already installed 2 speakers @ 4 ohms/550W. Question is, can I add 2 more speakers so i can utelized the 2x Left and 2x Right. And what kind of speaker should I add so that the speaking or voice volume will increase. Effects and other sound are too loud while I cant barely hear the speaking voice.

Thanks in adnvace.


This will probably make me sound a fair bit dense, but what do the 1s represent in the formula. Following the formula gives me the correct answer, but why do we divide one by the number of ohms?

Isaak (Chihuahua, Mexico)

Hi Geoff!

I have a amplifier and the lowest impedance rate of my amp is 2 ohms per channel

And I have 12 speakers of 8 ohm each and I need to connect 6 speakers on each channel

So my question is:
How can I wire up 6 speaker of 8 ohm each to get a total of 2 ohms load


Hugo Figueiredo (Lisbon, Portugal)

Hi Geoff ,

I have an amplifier Yamaha rx-v365 ( Built-in 5-channel power amplifier ,(1 kHz, 0.9% THD, 6 Ω) ,Front: 100 ,W/ch , Center: 100 W , Surround: 100 W/ch ) and i want to connect 3 speakers eatch side of the front ( 1 – 80w – 8 Ohms , 2 – 100w 8 ohms , 3 – 100w 8 Ohms ) , How should i connect ? Parallel or Series , to not burst with any of the speakers or amplifier ? Thank you for your patience .

AJ (Las Vegas, Nevada)

Designing Speaker System (Advice Needed) If I have a 700 Watt Stereo Power Amplifier (350 Watts Per Channel). I wish to wire a total of 8 speakers (4 Woofers each at 8 Ohms going to an inductor crossover & 4 Midrange Speakers each at 8 Ohms going through a 400 Volt Capacitor crossover) all together within one single speaker cabinet. How should I wire/configure this without overloading my power amplifier? 1. Woofer: Out of the four woofers (each 8 ohms) – can I safely wire each “pair” of woofers in series going to the amplifier; which will give me 4… Read more »

Pete Y (Austin)

Hi Geoff, I am looking for amp specifications to drive 6 8ohm speakers in a single outdoor room. The speakers are 150w RMS. Been through way too many articles and getting confused. Wiring 3 in parallel gets me to 2.67 ohm, but that seems pretty low. Wiring in series gets me to 24 ohm…is that just too high? Advice welcomed.

Kevin (TULSA)

I have an Episode 500 LCR speaker manufacturered by Snap AV

Link below ….


It is a 6 ohm speaker.

How can I rewire it so that all 3 channels operate as one ?

I’ve tried wiring it in series , doing it this way it sounds beautifully but it presents a 2 ohm load to the amplifier.

I’d like to rewire it so it works as a single 6 ohm speaker .

Currently my amplifier goes into safe mode and shuts down at high volume.